NASA's Phoenix lander, which was launched on 4 August 2007 on a Delta II rocket from Cape Canaveral Air Force Station in Florida, is due to touch down at the far north of the red planet on Monday, after a 423-million-mile journey from Earth.

The probe is equipped with a robotic arm to dig for water or ice thought to be buried beneath the surface.

Scientists say the mission should give the clearest indication yet of whether Mars could once have harboured life.

The final seven minutes of the probe's ten-month journey is regarded as "the riskiest" part of the mission.

After it enters the top of the Martian atmosphere at nearly 5.7km/s (13,000 mph), the probe must perform a series of manoeuvres.....obviously with point precision, to come safely to rest.

It will 1. release a parachute, 2. use pulsed thrusters to slow to a fast walking speed, then 3. come to a slow halt on three legs.

If all goes to plan, the Phoenix lander will reach the surface of Mars at 0623 IST tomorrow.

NASA has said that they will be able to determine success or failure within about 15 minutes of the landing .

David Catling from the University of Bristol is a co-investigator on the mission. He said the landing phase would be one of the most exciting and tense parts of the journey, with so much riding on Phoenix's safe descent.

If all goes to plan, Phoenix will begin a three-month mission to search for ice beneath the Martian surface.It will use a robotic arm to dig through the protective topsoil layer and lift samples of both soil and ice to its deck for scientific analysis.

Dr Tom Pike of Imperial College says,"The main goal of the mission is to get below the surface of Mars to where we are almost certain there is water. The orbiters that are around Mars have already surveyed in great detail the area in which we are landing and we know that there is ice - solid water - 10cm, or maybe even less, below the surface."

Landing on Mars has been amazingly difficult for NASA. Of the 11 missions that have tried to land probes on Mars since 1971 - only five have succeeded!!You can read about all of them here.In September 1999, theMars Climate Orbiter spacecraft crashed into the Red Planet following a navigation error caused when technicians mixed up "English" (imperial) and metric units.

A few months later, another NASA spacecraft, the Mars Polar Lander(MPL), was lost near the planet's South Pole.

And this time the mission targets the far north of Mars.... So the risk is far greater!!Here's a map showing the other Mars missions...

So now all we can do is pray that Phoenix lands safely!!Fly Phoenix, Fly!!

Water, of course, is of critical importance because it is one of the building blocks - one of the essential habitats we need - for life --Dr Tom Pike of Imperial College